A call admission control is a method for increasing quality of service (QoS), and it represents a process for a base station to determine whether to receive a call requested by a terminal by considering an available resource of the base station in the case of a new call/connection (referred to as a call hereinafter) or a handover. When the system resource is insufficient, the base station does not allow a new call/connection or a handover call, thereby maintaining the QoS of a service call provided to a terminal.
When the base station performs the call admission control, the new call and the handover call have different importance. The user's loss is not significant regarding rejection on the new call since the user can perform the call again later. However, rejection on the handover call generates a relatively great loss to the user since the service provided to the terminal is interrupted. Therefore, a policy of maintaining the dropping probability of a handover call to be less than the blocking probability of a new call is used by providing a predetermined priority to the handover call and then reserving the resource.
A user of the wireless Internet system is generally an Internet service user. Therefore, a user walking on the road as opposed to a user riding in a car frequently uses a service while staying at a specific location because of the characteristic of the data service. The above-noted user is called a stationary user.
When the stationary user continuously stays in the boundary area of a cell, resources reserved by base stations other than a valid base station from among the base stations in the active cell in which the stationary user belongs are provided as unused for a long time until the terminal is moved again, which deteriorates the system performance since the rejection rate of a new call or a handover call is increased when the system resource is insufficient.
Therefore, a method for detecting a stationary user and a method for controlling the balance of a load of the detected stationary user by instructing a handover to the base station having sufficient resources have been researched.
For example, a method for applying a common set of a current active cell and an active cell that is given after a predetermined time has passed to neighboring base stations of the active cell and detecting the same has been provided. That method provides two snapshots in the system and detects a common factor of the two snapshots. This method efficiently detects the stationary user when the progress type of the terminal is linear, but reduces the stationary user's accuracy when the terminal moves randomly.
In addition, another method is to detect a stationary user, cancel the resource reserve for the stationary user from the reserve for the handover call, separately manage the resource reserve, and control the canceled call to be shared by a new call or a handover call. Since the stationary user's reserve is provided as a reserve for the handover call, the rejection rate of the handover call is problematically increased when an error occurs while detecting the stationary user.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.